AUTONOMY
305	AVEENUS
than ever before and remove the "knocking"
that was so detrimental to engine efficiency,
but it also led to the development of a new
industry—the separation of bromine, which
is used in the manufacture of tetra-ethyl
lead, from sea water. Although this fluid
was added to premium gasolines after its
discovery, it is today used to treat practi-
cally all gasoline used by automobiles.
The research facilities of the industry are
now being devoted to such things as the
conditioning of air within the car body so
that it will be comfortable at all seasons;
the chemical treatment of oil to prevent it
from breaking down when subjected to the
high pressures and temperatures of today's
engine; the provision of oxygen-free metals
for sounder ingots and castings with greater
fatigue resistance; case-hardened glass of
the safety type; synthetic textile fibres for
interiors and insulation and the develop-
ment of new tough high-speed tool steels.
The industry is also paying much atten-
tion to the important question of safety in
driving. While it is agreed that the elimina-
tion of grade crossings and the building
of elevated and super-highways will go far
toward bringing down the accident rate in
automobile traffic, the industry looks for-
ward to the day when fool-proofing the
driver of the automobile will be of the ut-
most importance and benefit. The railroads
have accomplished the same results with
automatic train control which takes the
train out of the engineer's hands if he dis-
regards signals, slows it down and brings it
to a stop. Just what form this will take
with the automobile is still a matter of
conjecture.
Belated   Articles.     Consult   the   following
titles for additional information:
Carburetor	Horse Power
Biesel Engine	Pneumatic Tires
Gas Engine
AUTONOMY, awtahn'omi. An auton-
omous nation is one which is privileged to
govern itself without the interference of
foreign nations. The word is derived from
the Greek for self and law and it means,
literally, freedom in government. Canada
and South Africa enjoy autonomy within
the British Empire; after the Russian revo-
lution of 1917 the autonomy of Finland as a
republic was recognized by Russia, and in
1918 Denmark accorded like rights to Ice-
land.
AU'TUMJST, the season of the year be-
tween summer and winter. Astronomically
speaking, in the Northern Hemisphere this
season covers the period from the autumnal
equinox, about September 22, till the winter
solstice, December 22. Popularly, however,
in America the term autumn is used to de-
note the months of September, October and
November; and in England, to denote
August, September and October,
AVALANCHE. High up on the slopes
of lofty mountains great masses of snow and
ice accumulate. When these masses are
started in motion they slide down the moun-
tain with irresistible force, forming" what is
known as an avalanche. Avalanches are of
different classes. Those consisting of fine,
dry particles of snow driven down the moun-
tain by a strong wind are known as wind
or dust avalanches; those which consist of
great masses of snow sliding down a slope
by their own weight are known as sliding
avalanches; those which are detached by
heat from the high glaciers are known as
glacier or summer avalanches. The sliding
avalanche is the most dangerous of all, and
consists of vast accumulations of snow set
free from above, which increase in force as
they descend, overthrowing houses, tearing
up trees, burying villages and swallowing up
forests, cattle and human beings. An ava-
lanche which fell in the Alpine district of
Italy, in 1885, contained 250,000 tons of
snow.
AVE MABIA, dh'tHimdhreefdh (Hail,
Mary), the first two words of the angel
Gabriel's salutation to Mary (Luke I, 28), and
the beginning of the very common Latin
prayer to the Virgin in the Roman Catholic
Church. Its lay use was sanctioned at the
end of the twelfth century, and a Papal
edict of 1326 ordains the repetition of the
prayer thrice each morning, noon and even-
ing, at the hour indicated by the bells called
the Ave Maria or Angelus Domini.
AVER'NUS, a lake now called lago d'
avernq, in Campania, Italy, between the
ancient Cumae and Puteoli, about eight miles
from Naples, It occupies the crater of an
old volcano, and is in some places 180 feet
deep, formerly the gloom of its forest sur-
roundings and its sulphurous vapors caused
it to be regarded as the entrance to the in-
fernal regions. It was the fabled abode of
the Cimmerians, and was especially dedicated
to Proserpine.